Jump to content

Lever: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
m Reverted 1 edit by 1 drinkwiped for everyone (talk) identified as vandalism to last revision by Wayne Slam. (TW)
Line 24: Line 24:
In [[physics]], a '''lever''' (from [[French language|French]] ''lever'', "to raise", c.f. a ''[[levant]]'') is a rigid object that is used with an appropriate fulcrum or [[wiktionary:pivot|pivot]] point to multiply the mechanical force (effort) that can be applied to another object (load).
In [[physics]], a '''lever''' (from [[French language|French]] ''lever'', "to raise", c.f. a ''[[levant]]'') is a rigid object that is used with an appropriate fulcrum or [[wiktionary:pivot|pivot]] point to multiply the mechanical force (effort) that can be applied to another object (load).
This '''leverage''' is also termed [[mechanical advantage]], and is one example of the [[principle of moments]]. A lever is one of the six [[simple machine]]s.
This '''leverage''' is also termed [[mechanical advantage]], and is one example of the [[principle of moments]]. A lever is one of the six [[simple machine]]s.

== Libreoffice ==
{{Infobox software
| name = LibreOffice
| logo = [[File:LibreOfficelogo.svg|220px]]
| screenshot = [[File:LibreOffice startcentre.png|300px]]
| caption = Startcentre in LibreOffice 3.3.0 Beta 1
| developer = [[The Document Foundation]]
| released = {{Start date|2010|09|28}}
| discontinued =
| latest_release_version = None
| latest_release_date = <!-- {{Start date and age|YYYY|MM|DD|df=yes/no}} -->
| latest_preview_version = 3.3.0 RC 1
| latest_preview_date = {{Start date and age|2010|12|03|df=yes}}
| frequently_updated = <!-- DO NOT include this parameter unless you know what it does -->
| programming_language = [[C++]], [[Java (programming language)|Java]]
| operating_system = [[Linux]]<br /> [[Mac OS X]]<br /> [[Berkeley Software Distribution|BSD]]<br /> [[Unix]]<br /> [[Microsoft Windows|Windows]]
| platform = [[Cross-platform]]
| language =
| status =
| genre = [[Office suite]]
| license = [[GNU Lesser General Public License|GNU LGPL]]
| website = [http://www.documentfoundation.org/download/ www.documentfoundation.org/download/]
}}

'''LibreOffice''' is a productivity suite that is compatible with other major office suites, and available on a variety of platforms. The goal is to produce a vendor-independent office suite with [[ODF]] support and without any copyright assignment requirements. The name is a [[hybrid word]] with the first part ''Libre'', which means ''free'' [[Libre|(as in freedom)]] in both Spanish and French and the English word ''Office''. As [[free software]], users are free to download, modify, use and distribute LibreOffice.

==History==
[[File:LibreOffice Impress beta.png|thumb|Impress in LibreOffice 3.3.0 Beta 1]]
On September 28, 2010, some members of the [[OpenOffice.org]] Project formed a new group called [[The Document Foundation]], and made available a rebranded fork of OpenOffice.org which was based on OpenOffice.org 3.3 beta version. It was hoped that the LibreOffice name would be provisional as Oracle was invited to become a member of the Document Foundation, and was asked to donate the OpenOffice.org brand to the project.<ref>{{cite web
| last = | first =
| authorlink =
| coauthors =
| title = OpenOffice.org Community announces The Document Foundation
| work =
| publisher = [[The Document Foundation]]
| date = 2010-09-28
| url = http://www.documentfoundation.org/lists/announce/msg00000.html
| format =
| doi =
| accessdate = 2010-10-21
}}</ref>
As a result, LibreOffice uses the same version number as OpenOffice.org. At the end of October 2010, 33 German volunteers, not involved with development, left OpenOffice.org and moved to The Document Foundation to support LibreOffice.<ref name="Digitizor01Nov10">{{cite news
| url = http://digitizor.com/2010/11/01/and-so-the-exodus-begins-33-developers-leave-openoffice-org/
| title = And So The Exodus Begins – 33 Developers Leave OpenOffice.org
| accessdate = 2010-11-01
| last = Ricky
| authorlink =
| year = 2010 | month = November
| work = Digitizor
}}</ref>

The [[Go-oo]] project will be discontinued in favour of LibreOffice.<ref>[http://go-oo.org/ Go-oo homepage]</ref> Improvements made by the project are being merged into LibreOffice. Improvements made in other forks are expected to be incorporated into LibreOffice as well.<ref>{{cite web
| last = | first =
| authorlink =
| coauthors =
| title = The Document Foundation FAQ
| work =
| publisher = [[The Document Foundation]]
| date = 2010-09-28
| url = http://www.documentfoundation.org/faq/
| format =
| doi =
| accessdate = 2010-10-05
}}</ref><ref>{{cite web
| last = Edge | first = Jake
| authorlink =
| coauthors =
| title = Michael Meeks talks about LibreOffice and the Document Foundation
| work =
| publisher = [[Linux Weekly News]]
| date = 2010-09-28
| url = http://lwn.net/Articles/407339/
| format =
| doi =
| accessdate =
}}</ref>

[[Canonical Ltd.|Canonical]], [[Novell]] and [[Red Hat]] plan to include LibreOffice in upcoming versions of their [[operating system]]s.<ref name="collins-29-09-10">{{cite web
| last = Collins | first = Barry
| title = OpenOffice group breaks away from Oracle
| url = http://www.pcpro.co.uk/news/361516/openoffice-group-breaks-away-from-oracle
| publisher = PC Pro
| accessdate = 2010-09-29
}}</ref>


==Early==
==Early==

Revision as of 16:28, 9 December 2010

This article is about the simple machine. For other uses, see Lever (disambiguation).
Lever
Levers can be used to exert a large force over a small distance at one end by exerting only a small force over a greater distance at the other.
ClassificationSimple machine
IndustryConstruction

In physics, a lever (from French lever, "to raise", c.f. a levant) is a rigid object that is used with an appropriate fulcrum or pivot point to multiply the mechanical force (effort) that can be applied to another object (load). This leverage is also termed mechanical advantage, and is one example of the principle of moments. A lever is one of the six simple machines.

Libreoffice

LibreOffice
Developer(s)The Document Foundation
Initial releaseSeptember 28, 2010 (2010-09-28)
Stable release
None
Preview release
3.3.0 RC 1 / 3 December 2010; 13 years ago (2010-12-03)
Written inC++, Java
Operating systemLinux
Mac OS X
BSD
Unix
Windows
PlatformCross-platform
TypeOffice suite
LicenseGNU LGPL
Websitewww.documentfoundation.org/download/

LibreOffice is a productivity suite that is compatible with other major office suites, and available on a variety of platforms. The goal is to produce a vendor-independent office suite with ODF support and without any copyright assignment requirements. The name is a hybrid word with the first part Libre, which means free (as in freedom) in both Spanish and French and the English word Office. As free software, users are free to download, modify, use and distribute LibreOffice.

History

Impress in LibreOffice 3.3.0 Beta 1

On September 28, 2010, some members of the OpenOffice.org Project formed a new group called The Document Foundation, and made available a rebranded fork of OpenOffice.org which was based on OpenOffice.org 3.3 beta version. It was hoped that the LibreOffice name would be provisional as Oracle was invited to become a member of the Document Foundation, and was asked to donate the OpenOffice.org brand to the project.[1] As a result, LibreOffice uses the same version number as OpenOffice.org. At the end of October 2010, 33 German volunteers, not involved with development, left OpenOffice.org and moved to The Document Foundation to support LibreOffice.[2]

The Go-oo project will be discontinued in favour of LibreOffice.[3] Improvements made by the project are being merged into LibreOffice. Improvements made in other forks are expected to be incorporated into LibreOffice as well.[4][5]

Canonical, Novell and Red Hat plan to include LibreOffice in upcoming versions of their operating systems.[6]

Early

The earliest remaining writings regarding levers date from the 3rd century BC and were provided by Archimedes. "Give me a place to stand, and I shall move the earth with a lever" is a remark of Archimedes who formally stated the correct mathematical principle of levers (quoted by Pappus of Alexandria).[7]

It is assumed that in ancient Egypt, constructors used the lever to move and uplift obelisks weighting more than 100 tons [8].

Force and levers

The force applied (at end points of the lever) is proportional to the ratio of the length of the lever arm measured between the fulcrum (pivoting point) and application point of the force applied at each end of the lever.

Mathematically, this is expressed by , where is the force, is the distance between the force and the fulcrum, and is the turning force known as the moment or torque.

Classes

There are three classes of levers representing variations in the relative locations of the fulcrum, the load and the force:[9]

  • Class 1: The fulcrum is located between the applied force and the load, for example, a crowbar or a pair of scissors or a seesaw
  • Class 2: The load is situated between the fulcrum and the force, for example, a wheelbarrow or a nutcracker.
  • Class 3: The force is applied between the fulcrum and the load, for example, a tweezers or human mandible

In the real world

For the classical mechanics formulas to work, or to be a good approximation of real world applications, the lever must be made from a combination of rigid bodies, (i.e., a beam) and a rigid fulcrum. Any bending or other deformation must be negligible.

See also

References

  1. ^ "OpenOffice.org Community announces The Document Foundation". The Document Foundation. 2010-09-28. Retrieved 2010-10-21. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  2. ^ Ricky (2010). "And So The Exodus Begins – 33 Developers Leave OpenOffice.org". Digitizor. Retrieved 2010-11-01. {{cite news}}: Unknown parameter |month= ignored (help)
  3. ^ Go-oo homepage
  4. ^ "The Document Foundation FAQ". The Document Foundation. 2010-09-28. Retrieved 2010-10-05. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  5. ^ Edge, Jake (2010-09-28). "Michael Meeks talks about LibreOffice and the Document Foundation". Linux Weekly News. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  6. ^ Collins, Barry. "OpenOffice group breaks away from Oracle". PC Pro. Retrieved 2010-09-29.
  7. ^ Mackay, Alan Lindsay (1991). "Archimedes ca 287–212 BC". A Dictionary of scientific quotations. London: Taylor and Francis. p. 11. ISBN 9780750301060.
  8. ^ Budge, E.A. Wallis (2003). Cleopatra's Needles and Other Egyptian Obelisks‎. Kessinger Publishing. p. 28. ISBN 9780766135246.
  9. ^ Davidovits, Paul (2008), Physics in Biology and Medicine, Third edition, Academic Press, p. 10, ISBN 978-0-12-369411-9, Chapter 1, p. 10
Wikimedia Commons has media related to Levers.
Look up lever in Wiktionary, the free dictionary.
Retrieved from "https://wiki.riteme.site/w/index.php?title=Lever&oldid=401466846"